Simultaneous Control Information and Power Transmission for Reconfigurable Intelligent Surfaces

TL;DR

This paper explores wirelessly powering reconfigurable intelligent surfaces (RISs) through simultaneous wireless information and power transfer (SWIPT), proposing optimized methods for efficient control signal delivery and RIS reconfiguration.

Contribution

It introduces closed-form solutions for SWIPT receiver optimization in RIS control, addressing energy and information needs simultaneously.

Findings

Proposed methods effectively handle received power fluctuations.

Closed-form solutions enable efficient RIS control signal power management.

SWIPT principles ensure reliable RIS operation with minimal energy consumption.

Abstract

Reconfigurable intelligent surfaces (RISs) are planar structures with attached electronic circuitry that enable a partially programmable communication environment. RIS operation can be regarded as nearly passive since it acts by simply reflecting the impinging traveling waves towards desired directions, thus requiring energy only for the reconfiguration of its reflective elements (REs). This paper tackles the problem of wirelessly powering RIS circuitry via control signaling. Simultaneous wireless information and power transfer (SWIPT) is considered by taking into account two basic principles: that signal quality of the control signals is sufficient for information detection, and that there is enough harvested energy for the reconfiguration. Some of the most common SWIPT receivers (time sharing, power splitting, dynamic power splitting, and antenna selection) are studied and the corresponding proposed optimization problems implementing the aforementioned principles are formulated and solved in closed form. Numerical results show the effectiveness of the proposed methods in the presence of received power fluctuations.